Spokane — Hard work and $25,000 guaranteed that Spokane residents will be able to vote on adding fluoride to their water.

People for Healthy Teeth delivered 12,742 signatures to City Hall on Tuesday, 50 percent more than state law requires to place an initiative on the ballot.

While the city clerk’s office will have to validate the signatures, “I’m confident that we have enough,” said Dr. Mary Smith, chairwoman of the nonprofit group.

Smith, noting that People for Healthy Teeth didn’t start gathering signatures until after July 4, said the number of signees in such a short time represents a strong show of support for fluoridation.

But the group also had plenty of help. It paid professional signature gatherers $2 a signature and was prepared to spend a war chest of $29,000 on signature gathering, said John Robideaux, the group’s publicist.

Most of the funds were raised from dentists and others in the health care industry.

People for Healthy Teeth had little choice but to use paid signature gatherers if it was going to meet the deadline, Smith said.

“We were in a time crunch, and you do what you have to do, especially when you believe in something,” she said, adding that the volunteers also collected signatures.

By submitting its signatures, People for Healthy Teeth cleared a major hurdle to introducing fluoride to the city’s water, which Smith said is a safe, cheap and effective way to prevent tooth decay.

The next step is a media campaign in anticipation of the November vote.

“What we’re trying to do is educate the people who are undecided about the merits of fluoride,” Smith said.

There is vocal opposition to fluoridation, led locally by the Safe Water Coalition of Washington State. Its founder, Betty Fowler, derides fluoride’s supporters as using “junk science” to prove its benefits and said fluoride use can actually harm teeth.

Smith said her group wasn’t worried about reaching the small percentage of the population that will never support it.

“What we found out is that a far higher percentage of the population can’t believe we don’t have it in our water already,” she said.